<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        for (var i = 1; i <= 5; i++) {
console.log("我执行了一次");
if(i==4){
            break;
        }
        }
       
    </script>
</body>
</html>